48G Re-creation Project (fantasy)

[Claudio L.]

My 2 cents here:

Your definition of the project has me confused. On one hand you are talking about "recreating" on modern technology, then you jumped directly to Saturn emulation, but you want to recreate the computations in Python. First you need to define if you want "recreation" or "emulation". Emulation means you use HPs original ROM and you get full compatibility with the entire hpcalc.org repository. This is great... but it also means you are stuck with Saturn memory limits, low screen resolution, black and white... in other words, you can't add anything new.
The other option is recreate a similar interface, similar language from scratch, that can run in modern hardware AND take advantage of all other goodies that the new hardware will offer. You'll lose the full compatibility, even if it looks the same, code from hpcalc.org won't work without the Saturn emulation layer.
The good news for you is this other option already exists and it's called newRPL. It's open source, it will run baremetal on any ARM hardware that has an MMU without much effort. But... it won't be an HP48, it's a newRPL machine. It's different, modern and most 48 fans will feel at home with its interface, but it may not meet your goal of recreating an HP48.

As far as hardware, a Raspberry Pi is a bad choice for baremetal coding. Its Broadcom CPU has a weird way to boot, and needs proprietary drivers, which means you are stuck with Linux, can't go baremetal. It's a great board for people that code on top of Linux, though.